Performance of a laser frequency comb calibration system with a high-resolution solar echelle spectrograph

摘要

Laser frequency combs (LFC) provide a direct link between the radio frequency (RF) and the optical frequencyregime. The comb-like spectrum of an LFC is formed by exact equidistant laser modes, whose absolute opticalfrequencies are controlled by RF-references such as atomic clocks or GPS receivers. While nowadays LFCsare routinely used in metrological and spectroscopic fields, their application in astronomy was delayed untilrecently when systems became available with a mode spacing and wavelength coverage suitable for calibrationof astronomical spectrographs. We developed a LFC based calibration system for the high-resolution echellespectrograph at the German Vacuum Tower Telescope (VTT), located at the Teide observatory, Tenerife, CanaryIslands. To characterize the calibration performance of the instrument, we use an all-fiber setup where sunlightand calibration light are fed to the spectrograph by the same single-mode fiber, eliminating systematic effectsrelated to variable grating illumination.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.